1. Field of the Invention
The present invention relates to a headrest device suitable for use with a seat in a vehicle such as an automobile, vessel, airplane and the like, especially suitable for use with an automotive seat.
2. Description of the Prior Art
Some of the conventional headrest devices of this type are equipped with a height adjustment mechanism which is capable of varying the height of the head-rest device so as to suit many occupants of different sitting heights or their tastes.
As an example of the headrest devices of the above-mentioned type, there is proposed a headrest device in Japanese Utility Model Publication No. 122923 of 1976. In this prior art device, headrest stays to be fixed to a head rest body are respectively provided with engagement step portions axially disposed at required intervals, and holders which are fixed to a seat back of a seat and through which the headrest stays are respectively inserted are formed with notches. A spring rod is engaged with one of the engagement step portions of the headrest stays through one of the notches to lock the stays with respect to the associated holders. If a lock removing lever is pressed or operated, then the inclined surface of a push piece provided in the lock removing lever is allowed to push the spring rod in a direction to move away from the stay engagement step portion, removing the locking of the stays. In this removed condition, the headrest body can be moved upwardly or downwardly together with the stays, that is, the headrest device can be adjusted in height.
In the above-mentioned prior art headrest device, however, the adjustment of the height thereof must be carried out with both hands since the lock removing operation to remove the spring rod from the stay engagement step portions and the operation to move the headrest body upwardly or downwardly are performed separately, which means that the headrest device is not good in operationability. Also, it is complicated in construction; for example, the lock removing lever must be equipped separately from the stay holders. Further, it requires a large number of parts, takes much labor in assembling, and is expensive in costs.